JP2018006484A - Light diffusion member for interconnector, interconnector for solar cell, and solar cell module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light diffusion member for interconnector which is less likely to cause misalignment when being stuck on an interconnector for solar cell, and capable of suppressing occurrence of microcrack in the solar cell upon occurrence of rapid temperature change.SOLUTION: A light diffusion member 3 for interconnector is placed on the side of an interconnector 1 connecting adjacent solar cells 6 opposite to the solar cells 6. The light diffusion member 3 includes a light diffusion layer 3a containing resin and inorganic particles, and has total thickness of 20-80 μm, and tensile modulus of 150-25000 MPa.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light diffusing member for an interconnector that can be applied to a crystalline silicon solar cell or the like, an interconnector for a solar cell, and a solar cell module.

  The solar cell interconnector is a wiring material for collecting current by electrically connecting adjacent solar cells in a crystalline silicon solar cell or the like. This wiring material is composed of an all-surface solder-coated substrate, and after applying a base plating to a flat metal substrate made of copper or the like, the entire surface of the flat metal substrate is coated by solder hot dipping. It is formed by doing.

  As the above-mentioned all-surface solder-coated substrate, for example, a member obtained by performing Sn-Bi-Ag solder plating on the surface of a rectangular copper substrate is known, and this is applied to a solar cell interconnector. The technique which performs is proposed (for example, refer patent document 1). In the case of such an interconnector for solar cells, since it is composed of a flat metal substrate, the portion of the interconnector shades and blocks light, resulting in a reduction in power generation efficiency of the solar cells. It is a factor to make. Moreover, since the solder-plated metal itself also absorbs visible light, the reflected light is reduced, and the incident light cannot be used effectively. From such a viewpoint, various techniques for improving the power generation efficiency of solar cells have been proposed. For example, the surface of a solar cell (absorber) is formed by patterning a groove having a face angle of 60 degrees on an interconnector for solar cells and totally reflecting light reflected by the interconnector between glass and air. A method has been proposed in which light is efficiently incident on the light source (see, for example, Patent Document 2). The grooves in this case are patterned by using a diamond turning mandrel rolling technique on a tin-plated flat rectangular copper substrate.

  In the above method, although the light reflected by the solar cell interconnector can be used effectively, the patterned solder plating metal itself still absorbs visible light, so that the reflected light is 80%. May fall to the extent. In addition, since the above technique requires a separate pattern forming process, the manufacturing process is complicated. From such a viewpoint, for example, by providing a layer having a light diffusing function on the solar cell interconnector, it is conceivable to increase the amount of light incident on the surface of the solar cell to increase the power generation efficiency.

JP 2002-217434 A Special table 2009-518823

  When a layer having a light diffusing function (light diffusing layer) is provided on the interconnector for solar cells as described above, it is difficult to stick the light diffusing layer straight on the interconnector, resulting in deviation from the interconnector. As a result, the power generation efficiency of the solar battery cell may be reduced. In addition, the present inventors have found that when a light diffusion layer is provided, a sudden outdoor temperature change causes microcracks in the solar cells to cause a reduction in power generation efficiency of the solar cells, I arrived at the issue of the need to reduce it. Specifically, when a temperature cycle test between −40 ° C. and 85 ° C. is performed on the solar battery cell, the thermal stress due to the thermal expansion and contraction of the reflecting member propagates to the interconnector, and the soldered portion with the Ag electrode or the like As a result, it was found that microcracks that were not confirmed in the past have been generated.

The present invention has been made in view of the above, and it is difficult for deviation to occur when pasted on a solar cell interconnector, and microcracks of a solar cell when a sudden temperature change occurs. It is an object of the present invention to provide an interconnector light diffusing member capable of suppressing generation, an interconnector for solar cells and a solar cell module having the interconnector light diffusing member.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by setting the light diffusing member to a specific thickness and a specific tensile elastic modulus. It came to complete.

That is, the present invention includes, for example, the subject matters described in the following sections.
Item 1. A light diffusing member for an interconnector disposed on a surface opposite to the solar battery cell of an interconnector that connects adjacent solar battery cells,
A light diffusion layer including at least a resin and inorganic particles;
A light diffusing member for an interconnector having a total thickness of 20 µm or more and 80 µm or less and a tensile elastic modulus of 150 MPa or more and 25000 MPa or less.
Item 2. The resin is at least selected from the group consisting of ionomers, ethylene-vinyl acetate copolymers, ethylene- (meth) acrylic acid vinyl copolymers, adhesive polyolefin resins, acrylic resins, urethane resins, silicone resins, and unsaturated polyester resins. Item 2. The light diffusing member for an interconnector according to item 1, comprising one type.
Item 3. Item 3. The light diffusing member for an interconnector according to Item 1 or 2, wherein the light diffusing layer further contains a phosphor.
Item 4. Item 4. A solar cell interconnector comprising the interconnector light diffusing member according to any one of items 1 to 3.
Item 5. Item 5. A solar cell module comprising the solar cell interconnector according to item 4.

  The light diffusing member for an interconnector according to the present invention is less likely to be displaced when affixed along the interconnector for a solar battery, and even when a sudden temperature change occurs, the microcrack of the solar battery cell is generated. Can be suppressed.

  Since the interconnector for solar cells according to the present invention includes the light diffusing member for interconnector, the solar cell module can provide excellent power generation efficiency and can be suitably used for solar cells.

  Since the solar cell module according to the present invention includes the above-described solar cell interconnector as a constituent member, even if a sudden temperature change occurs, the occurrence of microcracks is suppressed, resulting in excellent power generation efficiency. Excellent durability.

It is a schematic sectional drawing which shows an example of embodiment of a solar cell module provided with the light-diffusion member for interconnectors of this invention. It is a top view of the solar cell module which does not provide the light diffusing member for interconnectors, and is a schematic diagram showing the state where the photovoltaic cells are connected by the interconnector. It is sectional drawing of a solar cell module same as the above, Comprising: It is a cross section of a solar cell module when cut along the aa line of FIG. It is a top view which shows an example of embodiment of a solar cell module provided with the light-diffusion member for interconnectors of this invention, and is the schematic which shows the state by which the light-diffusion member is provided in the interconnector. It is sectional drawing of a solar cell module same as the above, Comprising: It is a cross section of a solar cell module when cut along the bb line of FIG. It is a top view which shows an example of other embodiment of a solar cell module provided with the light-diffusion member for interconnectors of this invention, and is the schematic which shows the state by which the light-diffusion member is provided in the interconnector. An example of a method for adhering a light diffusing member for an interconnector to an interconnector is shown, (a) is a schematic diagram of each member used for adhering, and (b) is an adhesive for a light diffusing member for an interconnector to an interconnector. It is the schematic which shows a mode that it is made to do.

  Hereinafter, embodiments of the present invention will be described in detail.

  FIG. 1 is a schematic cross-sectional view showing an example of an embodiment of a solar cell module A provided with a light diffusing member 3 for an interconnector. The solar cell module A of this embodiment includes solar cells 6, an interconnector 1, an interconnector light diffusing member 3, a tempered glass 7, a sealing material 8, and a back surface protective sheet 9.

  The solar cell 6 is a member having a function of photoelectrically converting received light to generate electric power. A plurality of solar cells 6 are usually provided in the solar cell module A.

  2 and 3 respectively show a plan view and a cross-sectional view of a solar cell module in which the interconnector light diffusing member 3 is not provided. In FIG. 2, the tempered glass 7 and the sealing material 8 are omitted. 3 is a cross-sectional view taken along the line aa in FIG. 2. In FIG. 3, the tempered glass 7 and the sealing material 8 are shown.

  As can be seen from FIGS. 2 and 3, a plurality of solar cells 6 are provided in the vertical direction and the horizontal direction with a predetermined interval over substantially the entire surface of the solar cell module A, and are arranged in a grid pattern.

  The interconnector 1 is a member for electrically connecting adjacent solar cells, and is formed in, for example, a long ribbon shape (or tape shape) as shown in FIGS. The interconnector 1 is formed of a conductive member. In the adjacent solar cell 6, one end of the interconnector 1 is joined to the surface of one solar cell 6, and the other end of the interconnector 1 is joined to the back surface of the other solar cell 6. The six are electrically coupled to each other. In a single-sided light-receiving P-type silicon solar cell that is currently widely used, the light-receiving surface is a negative electrode and the non-light-receiving surface is a positive electrode. Usually, the interconnector 1 is electrically connected in series between the light receiving surface of the solar cell 6 and the non-light receiving surface of the other solar cell 6 as shown in FIGS. 2 and 3.

  4 and 5 respectively show a plan view and a cross-sectional view of a solar cell module provided with the light diffusing member 3 for an interconnector. In FIG. 4, the tempered glass 7 and the sealing material 8 are omitted. 5 is a cross-sectional view taken along the line bb in FIG. 4. In FIG. 5, the tempered glass 7 and the sealing material 8 are shown.

  An interconnector light diffusing member 3 (hereinafter sometimes abbreviated as “light diffusing member 3”) is provided on the surface of the interconnector 1 opposite to the solar battery cell 6 side. That is, the light diffusion member 3 is provided on the surface of the interconnector 1 on the sunlight receiving side. The light diffusing member 3 is a member having a function of diffusing and reflecting incident light. Details of the configuration of the light diffusion member 3 will be described later.

  As shown in FIGS. 4 and 5, the light diffusing member 3 can be arranged one by one for each interconnector, and in this way, productivity is increased in the manufacturing process of normal interconnector automatic wiring. It becomes good.

  As shown in FIG. 6, the light diffusing member 3 may be provided as one long sheet per cell string instead of the interconnector unit. However, in this case, since the sheet is long, it is necessary to perform alignment for each interconnector at once. Therefore, it is better to arrange the light diffusion member 3 with a predetermined length in the solar cell 6 as described above. It is preferable in the manufacturing process.

  The sealing material 8 is provided to seal and integrate the plurality of solar cells 6 and the interconnector 1. Thereby, the solar battery cell 6 is fixed in the solar battery module A. And the tempered glass 7 is bonded together to the surface side of this sealing material 8, ie, the sunlight light-receiving surface. On the other hand, a back surface protective sheet 9 is bonded to the back surface side of the sealing material 8.

  In the solar cell module A of the embodiment of FIG. 1, after sunlight enters from the tempered glass 7 side, the solar cell 6 receives this light and photoelectrically converts it to generate electric power.

  In particular, in the solar cell module A of the present embodiment, the light “incident light 4” incident on the interconnector 1 portion is diffused and reflected by the light diffusion member 3. The diffused and reflected light 5 is reflected by the tempered glass 7 and then received by the solar battery cell 6. Due to the diffusing action and reflecting action of incident light of the light diffusing member 3 as described above, the amount of light incident on the solar battery cell 6 increases as a whole, and as a result, the power generation efficiency of the solar battery module A can be improved.

  The interconnector light diffusion member 3 will be described in detail below.

  As shown in FIG. 1, the light diffusing member is disposed on the surface opposite to the solar cell 6 of the interconnector 1 that connects the adjacent solar cells 6. The light diffusing member according to the present embodiment includes a light diffusing layer 3a including at least a resin and inorganic particles. The surface opposite to the solar battery cell 6 of the interconnector 1 is a light receiving surface. The light diffusion member 3 has a total thickness of 20 μm or more and 80 μm or less, and a tensile elastic modulus of 150 MPa or more and 25000 MPa or less.

  The light diffusion layer 3a may be formed of a resin film, a resin sheet, or a resin plate containing inorganic particles. In this specification, a resin film, a resin sheet, or a resin plate may be collectively referred to as a “resin molded body”. In the resin molded body, resin is a matrix component, and inorganic particles are present in the matrix component.

  When the light diffusion layer 3a is a resin molded body containing inorganic particles, the type of the resin is not particularly limited, and a known resin can be used. Specific examples of the resin include, for example, high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene resin, and other polyolefin resins such as polybutene, acrylic resin, methacrylic resin, polyvinyl chloride resin, polystyrene resin. , Polyvinylidene chloride resin, saponified ethylene-vinyl acetate copolymer, polyvinyl alcohol resin, polycarbonate resin, fluorine resin (polyvinylidene fluoride, polyvinyl fluoride, ethylene detrafluoroethylene), polyvinyl acetate resin, Examples include acetal resins, polyester resins (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate), polyamide resins, and polyphenylene ether resins.

  Among these resins, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polypropylene resin, acrylic resin in that both the thickness and tensile elastic modulus of the light diffusing member 3 can be easily adjusted to the above range. It is preferable that The resin is more preferably a polypropylene resin or a linear low density polyethylene, and particularly preferably a polypropylene resin.

  The resin contained in the light diffusion layer 3a may be one type or two or more types. When two or more kinds of resins included in the light diffusion layer 3a are included, a so-called polymer blend, polymer alloy, or polymer composite may be used. The resin may be a copolymer or a graft polymer.

  The resin film or resin sheet can be formed, for example, by stretching in a uniaxial or biaxial direction. As the kind of resin when formed in this way, high-density polyethylene, low-density polyethylene, linear low-density polyethylene or It is preferable that the main component is polypropylene. As a molding method of the resin molded body, T-die molding or inflation molding can be adopted, and the molding can be performed with a multilayer extruder. The molecular weight of the resin plate is not particularly limited as long as it can be molded.

  The inorganic particles are an important material for imparting a light diffusion function and a light reflection function to the light diffusion layer 3a. The type of inorganic particles is not particularly limited, but for example, titanium oxide, silica, aluminum oxide, barium sulfate, germanium, zinc oxide, zinc sulfide, zinc carbonate, zirconium oxide, calcium carbonate, calcium fluoride, lithium fluoride, antimony, Magnesium oxide, vanadium oxide, tantalum oxide, cerium oxide, and the like can be used, and mica, titanium mica, talc, clay, kaolin, and the like can also be used. These may be used individually by 1 type and may use 2 or more types together. In addition, the inorganic particles may be in the form of a so-called complex oxide composed of oxides of a plurality of elements. Further, the surface of the inorganic particles may be further coated with other inorganic fine particles or organic fine particles.

  As the inorganic particles, it is particularly preferable to use titanium oxide from the viewpoints of high refractive index, low conductivity, heat and humidity resistance, temporal stability, price, and the like. The type of titanium oxide is not particularly limited, and rutile type titanium oxide, anatase type titanium oxide, and the like can be used, but excellent light diffusibility can be imparted, and a stable state can be maintained for a long period of time. In terms, rutile type titanium oxide is preferable.

  Although there is no restriction | limiting in particular of the average particle diameter of an inorganic particle, For example, it can be 200 nm or more and 300 nm or less. When the average particle diameter is 200 nm or more, the reflectance between wavelengths 800 to 1200 nm, which is near infrared light contributing to the power generation of the solar cell module A, can be increased, and higher power generation efficiency can be imparted. Moreover, if the average particle diameter is 200 nm or more, the catalytic activity due to the inorganic particles can be suppressed, so that the resin can be hardly deteriorated. On the other hand, if the average particle size is 300 nm or less, the reflectance between visible light 400 to 800 nm that greatly contributes to the power generation of the solar cell module A can be increased, and higher power generation efficiency can be imparted. It is known from the Planck's law that the light in the visible light region between 400 and 800 nm has a higher energy density than the light in the long wavelength region between 800 and 1200 nm. This is particularly advantageous for power generation. Therefore, an average particle diameter of 300 nm or less is particularly preferable in that the power generation efficiency of the solar cell module A is further increased. From the viewpoint of further improving the power generation efficiency of the solar cell module A, the average particle diameter of the inorganic particles is more preferably 210 nm or more and 290 nm or less. In addition, the average particle diameter here refers to the primary particle diameter of inorganic particles, and refers to an average value obtained by measuring the particle diameters of 10 samples of randomly selected primary particles by electron microscope observation.

  The light diffusing function of the light diffusing layer 3a is known to greatly depend on the refractive index difference between the resin and the inorganic particles and the particle diameter of the inorganic particles. Therefore, depending on the desired light diffusing function, the resin And a combination of inorganic particles may be selected.

  Inorganic particles are present in the matrix resin. The method for causing the inorganic particles to be present in the resin is not particularly limited. For example, if the resin molded body is molded in a state where the raw material resin and the inorganic particles are mixed in advance, a resin molded body containing inorganic particles is obtained. be able to.

  For the purpose of facilitating dispersion of the inorganic particles in the resin, the inorganic particles can be coated with a fatty acid such as stearic acid, a polyol that is a polyhydric alcohol, or the like. In this case, since the dispersibility of the inorganic particles in the resin is improved, the reflectance of the light diffusion layer 3a can be improved, and the power generation efficiency of the solar cell module A can be improved. There is no restriction | limiting in particular in the coating method, A well-known method is employable.

  The content of the inorganic particles is preferably 5.0% by mass or more and 60.0% by mass or less with respect to the total mass of the light diffusion layer 3a. The addition effect of an inorganic particle can fully be exhibited because an addition amount is 5.0 mass% or more. Moreover, when the addition amount is 60.0% by mass or less, it is possible to prevent a decrease in tensile strength and tear strength of the light diffusion layer 3a itself. A more preferable content of the inorganic particles is 10.0% by mass or more and 50.0% by mass or less with respect to the total mass of the light diffusion layer 3a.

  The light diffusion layer 3a formed including the resin and the inorganic particles may have a single layer structure or a multilayer structure formed by laminating a plurality of layers. In the case of a multilayer structure, all the layers may be made of the same material, or may be made of different materials. In particular, in the case of a multilayer structure, the type, particle diameter, content, and the like of inorganic particles added to each layer may be different among the layers. Specific examples of the multilayer structure include, for example, a laminate of the resin molded body and the metal foil. Examples of the metal foil include an aluminum foil.

  The light diffusion layer 3a is formed to contain the resin and inorganic particles, but other additives such as an antioxidant, an ultraviolet absorber, etc., as long as they do not hinder the light diffusion function of the light diffusion layer 3a. May be included.

  In particular, the light diffusion layer 3a can also contain a phosphor. Examples of the phosphor include phosphor particles that absorb ultraviolet rays having a wavelength of 300 to 400 nm and have a specific excitation peak between wavelengths 400 to 800 nm and can be converted into a visible light spectrum, so-called wavelength conversion particles. Illustrated. Since the light diffusion layer 3a contains the phosphor, ultraviolet rays that are not originally used for power generation are converted into visible light, so that the cell power generation efficiency can be further improved.

  When the light diffusing layer 3a contains a phosphor, the light diffusing layer 3a has a multilayer structure of two or more layers as described above, and a layer mainly containing phosphor particles in the outermost layer is on the surface opposite to the solar battery cell. The formation is a preferred embodiment of the light diffusing member 3. If it is the light-diffusion member 3 of this form, the visible light which wavelength-converted the incident ultraviolet rays, and the incident visible light can be diffused and reflected effectively, and can be again made incident on the photovoltaic cell 6.

  Examples of the phosphor particles include inorganic phosphors obtained by adding rare earth elements such as yttrium, europium and terbium to oxides such as aluminum oxide, organic phosphors such as cyanine dyes, and organic compounds such as alkyl groups on rare earth metals. A coordinated rare earth metal complex can be used. Among these, rare earth metal complexes are preferable from the viewpoints of wavelength conversion efficiency and long-term stability. The content of the phosphor particles is preferably 0.1% by mass or more and 10.0% by mass or less with respect to the total mass of the light diffusion layer 3a. When the addition amount is 0.1% by mass or more, the effect of adding the phosphor particles can be sufficiently exerted. Moreover, when the addition amount is 10.0% by mass or less, it is possible to prevent a decrease in tensile strength and tear strength of the light diffusion layer 3a itself.

  As in the embodiment of FIG. 1, the light diffusion member 3 may include an adhesive layer 3 b for bonding the light diffusion member 3 to the interconnector 1 in addition to the light diffusion layer 3 a. As shown in FIG. 1, the adhesive layer 3b is provided by being laminated on the back surface side of the light diffusion layer 3a, that is, the surface on the solar cell 6 side. By having the adhesive layer 3b, the light diffusing member 3 is easily adhered to the interconnector 1, and the adhesiveness between the light diffusing member 3 and the interconnector 1 is improved.

  In this case, the adhesive layer 3b can be formed of a resin that exhibits good adhesion to the interconnector 1 and the light diffusion layer 3a. Examples of the resin for forming the adhesive layer 3b include adhesive polyolefin such as polyethylene and polypropylene having adhesiveness, ethyl cellulose, nitrocellulose, polyvinyl butyral, phenol resin, melanin resin, urea resin, xylene resin, and alkyd resin. , Unsaturated polyester resin, (meth) acrylic resin, polyimide resin, furan resin, urethane resin, epoxy resin, thermosetting resin such as isocyanate compound and cyanate compound, polystyrene, ABS resin, polymethyl methacrylate, polyvinyl chloride, poly Vinylidene chloride, polyvinyl acetate, polyvinyl alcohol, polyacetal, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyphenylene oxide, polysulfone, polyi De, polyether sulfone, polyarylate, polyether ether ketone, polyethylene tetrafluoride, silicone resins, ionomer resins, ethylene - vinyl acetate copolymers and the like. These resins may be used alone or in combination of two or more. Among the resins listed above as examples, ionomer resins, ethylene-vinyl acetate copolymers, ethylene- (meth) acrylic acid copolymers, adhesive polyolefins in that they have good adhesion to the interconnector 1. Resins, acrylic resins, urethane resins, silicone resins, and unsaturated polyester resins are preferred. The adhesive polyolefin resin refers to a modified resin in which a reactive functional group is graft-modified to a polyolefin resin. For example, the reactive functional group is an unsaturated carboxylic acid. Examples of such adhesive polyolefin resins include graft-modified polyethylene resins, graft-modified ethylene / ethyl acrylate copolymer resins, graft-modified ethylene / vinyl acetate copolymer resins, graft-modified polypropylene resins, polybutene-1, poly- Examples include resins obtained by graft-modifying an α-olefin such as 4-methylpentene-1 or an ethylene / α-olefin copolymer resin with an unsaturated carboxylic acid or the like. Specific examples of the commercially available adhesive polyolefin resin include an adhesive polyolefin “Admer” (registered trademark) manufactured by Mitsui Chemicals, and more specifically, “Admer LF128” (registered trademark). The ionomer resin is a generic term for polymer metal salts having an acidic group such as a carboxylic acid or a sulfonic acid group in the polymer side chain, and a part or all of these acidic groups being a metal salt. In the present invention, the type is not particularly limited as long as it is an ionomer resin belonging to this definition.

  The adhesive layer 3b can be formed by applying an adhesive or a pressure-sensitive adhesive to the light diffusion layer 3a, and a method of attaching a pressure-sensitive adhesive that has been processed in advance into a film shape or a tape shape is also possible. These adhesives and pressure-sensitive adhesives are also preferably made of the resin systems exemplified above, and are particularly preferably made of acrylic resin, urethane resin, silicon resin, and unsaturated polyester resin from the viewpoint of weather resistance.

  When the light diffusing member 3 is formed with the light diffusing layer 3a and the adhesive layer 3b, the light diffusing member 3 is a member having both a light diffusing function and an interconnector adhering function. Such a light diffusing member 3 can be obtained by, for example, so-called two-layer coextrusion of the light diffusing layer 3a and the adhesive layer 3b. The two-layer coextrusion can employ a known method, and can generally be performed by a method similar to the method for producing a multilayer film.

  The adhesive layer 3b may contain the inorganic particles described above.

  The light diffusing member 3 does not necessarily need to have the adhesive layer 3b, and may be composed of only the light diffusing layer 3a. In this case, it is preferable that the resin constituting the light diffusion layer 3a further contains a resin having adhesion for the purpose of imparting the light diffusion layer 3a with adhesiveness to the interconnector 1. Examples of the resin having adhesiveness include the same materials as those used for the above-described adhesive layer 3b. Specific examples of the adhesive resin include a modified polyolefin resin and an ionomer resin having an adhesive property. Examples thereof include an adhesive polyolefin “Admer” (registered trademark) manufactured by Mitsui Chemicals.

  The light diffusing member 3 has a total thickness of 20 μm or more and 80 μm or less.

  When the total thickness of the light diffusing member 3 is less than 20 μm, it is easy to cause breakage and dimensional change, and workability is remarkably deteriorated. Therefore, it becomes difficult to apply the light diffusing member 3 straight to the surface of the straight interconnector 1. Misalignment from the interconnector 1 is likely to occur. Thereby, the light diffusion effect of the light diffusing member 3 is not sufficiently obtained, and the power generation efficiency of the solar cell module A is reduced.

  If the total thickness of the light diffusing member 3 exceeds 80 μm, microcracks are likely to occur in the solar battery cells 6, leading to a reduction in power generation efficiency of the solar battery module A. When the total thickness of the light diffusing member 3 exceeds 80 μm, a step between the light diffusing member 3 and the solar battery cell 6 occurs. Starting from this step, the light diffusing member 3 and the sealing material 8 located on the upper part are repeatedly expanded and contracted by a cycle between a high temperature and a low temperature. As a result, the solar cell 6 and the interconnector 1 Stress is applied to the joint, and microcracks occur in the 6 solar cells. If the total thickness of the light diffusing member 3 is 80 μm or less, expansion and contraction in the thickness direction of the light diffusing member 3 due to a cycle of high and low temperatures is suppressed, and the step is also reduced. The stress due to expansion and contraction can be alleviated, thereby making it easier to prevent the occurrence of microcracks in the solar battery cell 6. The total thickness of the light diffusing member 3 is particularly preferably 30 μm or more and 60 μm or less.

  The total thickness of the light diffusing member 3 means the total thickness of the light diffusing layer 3a when the light diffusing member 3 is composed of only the light diffusing layer 3a. When the light diffusing member 3 is a laminate of the light diffusing layer 3 a and the adhesive layer 3 b, the total thickness of the light diffusing layer 3 a and the adhesive layer 3 b is the total thickness of the light diffusing member 3. When the light diffusing member 3 has other layers in addition to the light diffusing layer 3a and the adhesive layer 3b, each layer including other layers in addition to the light diffusing layer 3a and the adhesive layer 3b is used. The total thickness is the total thickness of the light diffusing member 3.

  In the light diffusing member 3, the thickness of the adhesive layer 3 b is not limited, and can be, for example, 0.1 μm to 80 μm. If the adhesive layer 3b contains inorganic particles, the adhesive layer 3b can also be a reflective layer. Therefore, the thickness of the adhesive layer 3b may be adjusted as appropriate.

  If the tensile elastic modulus of the light diffusing member 3 is 150 MPa or more and 25000 MPa or less, the elasticity of the light diffusing member 3 becomes appropriate and can have a so-called stiffness, so that the mechanical characteristics are improved and the light is transmitted onto the interconnector 1. The diffusion member 3 can be affixed more accurately. When the tensile elastic modulus of the light diffusing member 3 is less than 150 MPa, the light diffusing member 3 is deflected and the linearity is lost. Therefore, the light diffusing member 3 is attached straight to the surface of the straight interconnector 1. It becomes difficult to cause deviation from the interconnector 1. Thereby, the light diffusion effect of the light diffusing member 3 is not sufficiently obtained, and the power generation efficiency of the solar cell module A is reduced. When the tensile elastic modulus of the light diffusing member 3 exceeds 25000 MPa, the light diffusing member 3 becomes difficult to adhere to the interconnector 1. That is, in this case, since the stiffness of the light diffusing member 3 is too strong for the adhesive force between the interconnector 1 and the light diffusing member 3, the light diffusing member 3 is easily peeled off from the interconnector 1 and pasted. I can't. The tensile elastic modulus of the light diffusing member 3 is particularly preferably 300 MPa to 4000 MPa.

  The light diffusing member 3 is disposed on the surface of the interconnector 1 opposite to the solar battery cell 6. For example, the light diffusing member 3 is bonded to the surface of the interconnector 1 opposite to the solar battery cell 6. The light diffusing member 3 can be provided on the entire surface or a part of the interconnector 1, but is preferably provided on the entire surface of the interconnector 1 from the viewpoint of further improving the power generation efficiency of the solar cell module A.

  As in the embodiment shown in FIG. 1, in the solar cell module A including the interconnector 1 provided with the light diffusing member 3, the incident light 4 incident from the tempered glass 7 is diffused and reflected by the light diffusing member 3. The diffused and reflected light 5 is reflected again by the tempered glass 7 and enters the solar battery cell 6. As a result, the amount of light incident on the solar battery cell 6 increases. Thus, by providing the interconnector 1 provided with the light diffusing member 3 excellent in light reflection performance and diffusion performance, incident sunlight can be used more efficiently, and the power generation efficiency of the solar cell module A Can be increased.

  The light diffusing member 3 preferably has an average absorption rate of visible light having a wavelength of 400 nm or more and 800 nm or less of 10% or less and a light diffusion rate of 90% or more. When the average absorptance of visible light having a wavelength of 400 nm to 800 nm is 10% or less, the visible light reflection performance of the light diffusing member 3 is further enhanced, and high power generation efficiency can be imparted to the solar cell module A. . Moreover, when the light diffusivity is 90% or more, the light diffusing performance of the light diffusing member 3 becomes better, and high power generation efficiency can be imparted to the solar cell module A. The light diffusivity here refers to the average value of the L * value at a reflection angle of 45 degrees at 45 degrees incidence and the L * value at a reflection angle of 75 degrees at 45 degrees incidence, and the reflection angle at 45 degrees incidence. It is a value defined by a value divided by an L * value of 15 degrees. The average absorption rate of visible light of the light diffusing member 3 can be measured with a commercially available spectroscope such as “V-570” manufactured by JASCO, and the light diffusivity can be measured with a commercially available multi-angle spectrocolorimeter such as X. It can be measured with a MA68IINS multi-angle spectrocolorimeter manufactured by Wright. The light diffusivity can be said to be an index representing the extent of light spread.

  In the embodiment of FIG. 1, the light diffusion layer 3 a is formed of a resin molded body such as a resin film as described above, but is not limited thereto, and is, for example, a coating film formed using an ink composition. It may be formed.

  The ink composition is composed of a liquid containing a resin and the above-described inorganic particles.

  As the resin in the ink composition, known resins can be used. For example, ethyl cellulose, nitrocellulose, polyvinyl butyral, phenol resin, melanin resin, urea resin, xylene resin, alkyd resin, unsaturated polyester resin, acrylic resin , Polyimide resin, furan resin, urethane resin, epoxy resin, thermosetting resin such as isocyanate compound and cyanate compound, polyethylene, polypropylene, polystyrene, ABS resin, polymethyl methacrylate, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, Polyvinyl alcohol, polyacetal, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyphenylene oxide, polysulfone, polyimide, polyethersulfur Emissions, polyarylate, polyether ether ketone, polyethylene tetrafluoride, silicone resins, and the like. These resins may be used alone or in combination of two or more.

  If the main component of the resin is a curable resin such as a mixture of an acrylate monomer and an epoxy resin, it may further contain a curing agent represented by an amine compound.

  The resin in the ink composition may be dissolved or dispersed in a solvent. Examples of the solvent include diethylene glycol monobutyl ether, diethylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether and the like, and other known organic solvents can also be used.

  The ink composition may contain various additives. Examples of additives include leveling agents, antioxidants, corrosion inhibitors, antifoaming agents, thickeners, tack fires, coupling agents, electrostatic imparting agents, polymerization inhibitors, thixotropic agents, and anti-settling agents. Can be mentioned. More specifically, a polyethylene glycol ester compound, a polyethylene glycol ether compound, a polyoxyethylene sorbitan ester compound, a sorbitan alkyl ester compound, an aliphatic polyvalent carboxylic acid compound, a phosphate ester compound, an amide amine salt of polyester acid, a polyethylene oxide type Examples thereof include compounds and fatty acid amide waxes.

  The content of the inorganic particles is preferably 5.0% by mass or more and 60.0% by mass or less with respect to the total mass of the ink composition. The addition effect of an inorganic particle can fully be exhibited because an addition amount is 5.0 mass% or more. Moreover, when the addition amount is 60.0% by mass or less, it is possible to prevent a decrease in tensile strength and tear strength of the light diffusion layer 3a itself. A more preferable content of the inorganic particles is 10.0% by mass or more and 50.0% by mass or less with respect to the total mass of the light diffusion layer 3a.

  In the ink composition, the total amount of the resin, the solvent and other additives can be 15% by mass or more and 60% by mass or less based on the total amount of the ink composition. In this case, it becomes easy to form a good light diffusing layer 3a because the ink applicability is good, and also prevents the drying property of the light diffusing layer 3a from deteriorating due to an increase in ink viscosity or the presence of excessive resin. It becomes easy to do.

  The blending ratio of the resin with respect to the total amount of the resin, solvent and other additives is not particularly limited, but is preferably 50% by mass or less. Moreover, although the mixture ratio of an additive is not specifically limited, It is preferable that it is 10 mass% or less.

  The light diffusion layer 3a can be formed by directly applying the ink composition to the interconnector 1 and then drying it. Thus, when forming the light-diffusion layer 3a from an ink composition, since the light-diffusion layer 3a itself has an adhesive function, even if it does not provide the adhesive layer 3b like embodiment of FIG. The light diffusion layer 3a is adhered to the interconnector 1. In this way, the light diffusing member 3 is provided in the interconnector 1. About the thickness of the light-diffusion layer 3a, it is the same as that of the case of embodiment of FIG. Moreover, even if it is the light-diffusion member 3 formed from an ink composition, it has the same performance as the light-diffusion member 3 formed with the above-mentioned resin molding. A preferred embodiment of the light diffusing member 3 formed from the ink composition is also the same as the light diffusing member 3 formed from the above-described resin molded body.

  Even in the light diffusing member 3 formed as described above, the solar cell module A including the interconnector 1 having the light diffusing member 3 has the same light diffusing function as the embodiment of FIG. Has excellent power generation efficiency by the same principle as described above.

  In the solar cell module A, the types of members other than the light diffusion member 3 are not particularly limited as long as they are members conventionally used in solar cells. For example, as the solar battery cell 6, a cell generally used in a crystalline silicon solar battery can be applied.

  Moreover, the method similar to the past can be adopted as a method of manufacturing the solar cell module A.

  In providing the light-diffusion member 3 in the interconnector 1, it can carry out in the state in which the interconnector 1 was attached to the photovoltaic cell 6. FIG. In this case, the light diffusing member 3 is not necessarily provided over the entire length of the interconnector 1, and the light diffusing member 3 is at least on the surface side of the portion of the interconnector 1 placed on the surface of the solar battery cell 6. It only has to be provided. The interconnector 1 is attached to the solar cell 6 by soldering to the light receiving surface of the solar cell 6 and the non-light receiving surface of the solar cell 6 adjacent thereto. In this way, the light diffusing member 3 can be bonded to the surface of the interconnector 1 opposite to the surface soldered to the string in which a plurality of cells are connected in series.

  The method of adhering the light diffusing member 3 to the interconnector 1 is not particularly limited. For example, when the light diffusing layer 3a is formed of a resin molded body, the light diffusing member 3 is subjected to heat pressing such as heat sealing. The diffusion member 3 can be bonded to the interconnector 1. If the light diffusing member 3 includes the light diffusing layer 3a and the adhesive layer 3b, the surface on the adhesive layer 3b side may be bonded to the surface of the interconnector 1. On the other hand, when the light diffusing member 3 is provided on the interconnector 1 using the ink composition, the ink composition may be applied to the interconnector 1 and then dried to form a film. As the coating conditions and drying conditions, the conditions generally used for forming a coating film can be adopted. The solar cell interconnector 1 including the light diffusing member 3 can be manufactured by any of the above methods.

  7A and 7B schematically show a method of bonding the light diffusing member 3 to the interconnector 1. In this bonding method, the light diffusing member 3 is bonded to the interconnector 1 attached to the solar battery cell 6 using the cart 80.

  The cart 80 includes a cart body 81, a roller portion 82, and a groove portion 83.

  The cart body 81 has a sloped portion 81a. The slope 81a is formed so as to incline downward from the top upper end of the carriage body 81 toward the bottom.

  The groove part 83 is formed in a groove shape along the slope direction of the slope part 81a. The groove 83 is formed with the same width as the width of the light diffusing member 3 or a width larger than the width of the light diffusing member 3. A plurality of groove portions 83 are formed on the slope portion 81 a with a predetermined interval, and the interval between the adjacent groove portions 83 and 83 is equal to the interval between the adjacent interconnectors 1 and 1 attached to the solar battery cell 6.

  The roller part 82 is provided in the bottom part of the trolley | bogie main body 81, and plays the role as a wheel which makes the trolley | bogie 80 reciprocate in one direction and the reverse direction. The roller portion 82 is placed on a mold 90 having a pair of rails 91 and 91. The roller portion 82 of the carriage 80 is placed so as to span the pair of rails 91, 91, whereby the carriage 80 can reciprocate the pair of rails 91, 91.

  In order to bond the light diffusing member 3 to the interconnector 1 by the carriage 80, first, as shown in FIG. 7B, one solar battery cell 6 is positioned between the pair of rails 91, 91 of the mold 90. The mold 90 is placed so that the pair of rails 91 and 91 and the longitudinal direction of the interconnector 1 are parallel to each other. Next, one end of the light diffusing member 3 is bonded to the surface of the interconnector 1, and the other end is held so as to fit into the groove 83. In this state, by sliding on the rail 91 while pulling the gripping portion 84 of the carriage 80, the light diffusing member 3 fitted in the groove 83 slides down to the upper part of the interconnector 1, thereby the light diffusing member. 3 is bonded onto the interconnector 1. By the above operation, the light diffusing member 3 is bonded to at least a portion of the interconnector 1 placed on the solar battery cell 6. For example, the light diffusion member 3 is bonded onto the interconnector 1 by thermocompression bonding.

  As shown in FIG. 7B, the light diffusing member 3 is adhered to the interconnector 1 using the carriage 80, so that the light diffusing member 3 is not easily displaced from the interconnector 1, and the light diffusing member 3 is more accurately connected to the interconnector. 1 can be pasted together.

  In addition, when the interconnector 1 is bonded to the solar battery cell 6, the light diffusing member 3 is usually provided in advance on the surface of the interconnector 1 opposite to the surface to be soldered with the cell light receiving surface. The interconnector 1 may be adhered to the solar battery cell 6. In this case, the surface of the interconnector 1 opposite to the surface on which the light diffusing member 3 is provided is soldered to the light receiving surface of the solar cell 6, and the interconnector 1 is connected to the adjacent solar cell 6. Connect to non-light-receiving surface. If it does so, in the state where solar cell module A was completed, light diffusion member 3 will be arranged on the light-receiving side (the surface side of solar cell module A), such as sunlight.

  In the solar cell module A in which the solar cell interconnector 1 including the light diffusing member 3 is incorporated, the light diffusing member 3 has a light diffusing function and a light reflecting function. The amount of light can be further increased. As a result, the solar cell module A has excellent power generation efficiency.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to the aspect of these Examples.

Example 1
A light diffusing member for an interconnector (hereinafter abbreviated as “light diffusing member”) comprising a light diffusing layer having a thickness of 60 μm and an adhesive layer having a thickness of 20 μm was manufactured. The light diffusion layer melts 75 parts by mass of polypropylene resin ("Prime Polypro F-300SP" manufactured by Prime Polymer Co., Ltd.) and 25 parts by mass of rutile titanium oxide (CR-63 manufactured by Ishihara Sangyo Co., Ltd.) having an average particle diameter of 210 nm. Made by kneading. In this light diffusion layer, the content of titanium oxide is 25 wt%. On the other hand, the adhesive layer was composed of 75 parts by mass of an adhesive polyolefin resin (“Admer LF128” (registered trademark) manufactured by Mitsui Chemicals, Inc.) and 25 masses of rutile titanium oxide (CR-63, manufactured by Ishihara Sangyo Co., Ltd.) having an average particle size of 210 nm. The part was manufactured by melt-kneading. In this adhesive layer, the content of titanium oxide is 25 wt%. By coextruding these light diffusion layers and adhesive layers, a two-layer coextruded film formed by laminating the light diffusion layers and the adhesive layers was obtained as a light diffusion member. This light diffusing member is described as “Ti25% -PP60 / Ti25% -ad20” in Table 1 below.

(Example 2)
A light diffusing member was obtained in the same manner as in Example 1 except that the thickness of the light diffusing layer was changed to 40 μm. This light diffusing member is described as “Ti25% -PP40 / Ti25% -ad20” in Table 1 below.

(Example 3)
A light diffusing member was obtained in the same manner as in Example 1 except that the thickness of the light diffusing layer was changed to 20 μm. This light diffusing member is described as “Ti25% -PP20 / Ti25% -ad20” in Table 1 below.

Example 4
A light diffusing member was obtained in the same manner as in Example 1 except that the thickness of the light diffusing layer was changed to 20 μm and the thickness of the adhesive layer was changed to 40 μm. This light diffusing member is expressed as “Ti25% -PP20 / Ti25% -ad40” in Table 1 below.

(Example 5)
A light diffusing member for interconnector (hereinafter abbreviated as “light diffusing member”) composed of a 10 μm thick light diffusing layer and a 10 μm thick adhesive layer was produced. For the light diffusion layer, 65 parts by mass of polypropylene resin ("Prime Polypro F-300SP" manufactured by Prime Polymer Co., Ltd.) and 35 parts by mass of rutile titanium oxide (CR-63 manufactured by Ishihara Sangyo Co., Ltd.) having an average particle diameter of 210 nm are melted. Made by kneading. In this light diffusion layer, the content of titanium oxide is 35 wt%. On the other hand, the adhesive layer was made of 65 parts by mass of an adhesive polyolefin resin (“Admer LF128” (registered trademark) manufactured by Mitsui Chemicals, Inc.) and 35 masses of rutile titanium oxide (CR-63, manufactured by Ishihara Sangyo Co., Ltd.) having an average particle size of 210 nm. The part was manufactured by melt-kneading. In this adhesive layer, the content of titanium oxide is 35 wt%. By coextruding these light diffusion layers and adhesive layers, a two-layer coextruded film formed by laminating the light diffusion layers and the adhesive layers was obtained as a light diffusion member. This light diffusing member is expressed as “Ti35% -PP10 / Ti35% -ad10” in Table 1 below.

(Example 6)
An acrylic pressure-sensitive adhesive (manufactured by Sumitomo 3M Co., Ltd.) is applied to the poppy surface of a single glossy soft aluminum foil having a thickness of 10 μm so that the pressure-sensitive adhesive layer has a thickness of 10 μm, dried, and a 30 μm polyethylene resin ( After melt-kneading 65 parts by mass of LLDPE Ultozex 4020L manufactured by Prime Polymer Co., Ltd. and 35 parts by mass of rutile titanium oxide (CR-63 manufactured by Ishihara Sangyo Co., Ltd.) having an average particle size of 210 nm, extrusion lamination is performed. Thus, a light diffusing member was obtained. This light diffusing member is described as “Ti35% -LL30 / AL10 / ad10” in Table 1 below.

(Comparative Example 1)
A light diffusing member for interconnector (hereinafter abbreviated as “light diffusing member”) composed of a 50 μm thick light diffusing layer and a 50 μm thick adhesive layer was produced. The light diffusion layer is obtained by melting and kneading 75 parts by mass of a polyethylene resin (LLDPE Ultzex 4020L manufactured by Prime Polymer Co., Ltd.) and 25 parts by mass of rutile titanium oxide (CR-63 manufactured by Ishihara Sangyo Co., Ltd.) having an average particle diameter of 210 nm. Produced. In this light diffusion layer, the content of titanium oxide is 25 wt%. On the other hand, the adhesive layer was composed of 75 parts by mass of an adhesive polyolefin resin (“Admer LF128” (registered trademark) manufactured by Mitsui Chemicals, Inc.) and 25 masses of rutile titanium oxide (CR-63, manufactured by Ishihara Sangyo Co., Ltd.) having an average particle size of 210 nm. The part was manufactured by melt-kneading. In this adhesive layer, the content of titanium oxide is 25 wt%. By coextruding these light diffusion layers and adhesive layers, a two-layer coextruded film formed by laminating the light diffusion layers and the adhesive layers was obtained as a light diffusion member. This light diffusing member is expressed as “Ti25% -LL50 / Ti25% -ad50” in Table 1 below.

(Comparative Example 2)
A light diffusing member was obtained in the same manner as in Comparative Example 1 except that the thickness of the light diffusing layer was changed to 30 μm and the thickness of the adhesive layer was changed to 30 μm. This light diffusing member is expressed as “Ti25% -LL30 / Ti25% -ad30” in Table 1 below.

(Comparative Example 3)
A light diffusing member was obtained in the same manner as in Comparative Example 1 except that the thickness of the light diffusing layer was changed to 60 μm and the thickness of the adhesive layer was changed to 60 μm. This light diffusing member is expressed as “Ti25% -LL30 / Ti25% -ad30” in Table 1 below.

(Comparative Example 4)
A light diffusing member was obtained in the same manner as in Example 1 except that the thickness of the light diffusing layer was changed to 40 μm and the thickness of the adhesive layer was changed to 60 μm. This light diffusing member is described as “Ti25% -PP40 / Ti25% -ad60” in Table 1 below.

(Comparative Example 5)
A light diffusing member was obtained in the same manner as in Example 1 except that the thickness of the light diffusing layer was changed to 5 μm and the thickness of the adhesive layer was changed to 5 μm. This light diffusing member is described as “Ti35% -PP5 / Ti35% -ad5” in Table 1 below.

(Comparative Example 6)
An acrylic pressure-sensitive adhesive (manufactured by Sumitomo 3M Co., Ltd.) is applied to the poppy surface of a single glossy soft aluminum foil having a thickness of 20 μm so that the pressure-sensitive adhesive layer has a thickness of 10 μm and dried. After melt-kneading 65 parts by mass of LLDPE Ultozex 4020L manufactured by Prime Polymer Co., Ltd. and 35 parts by mass of rutile titanium oxide (CR-63 manufactured by Ishihara Sangyo Co., Ltd.) having an average particle size of 210 nm, extrusion lamination is performed. Thus, a light diffusing member was obtained. This light diffusing member is described as “Ti35% -LL20 / AL20 / ad10” in Table 1 below.

(Evaluation method)
<Tensile modulus>
The stiffness of the light diffusing member was evaluated by measuring the tensile elastic modulus using the light diffusing member obtained in each of Examples and Comparative Examples.

  For measurement of the tensile elastic modulus, an autograph (VGS1-E) manufactured by Toyo Seiki was used. As a measuring method, a sample having a width of 10 mm and a length of 50 mm or more was prepared in accordance with JIS K7161, and a tensile test was performed at a measurement distance (chuck distance) of 50 mm at a speed of 200 mm / min. The length direction of the measurement sample was unified in the flow direction.

<Pasteability evaluation>
The sticking property of the light diffusing member to the interconnector cell was evaluated by a method using the cart 80 shown in FIG. First, the mold frame 90 was placed on a flat hot plate heated to 100 ° C., and the carriage 80 was placed so that the pair of rails 91 and 91 could be hung. Next, the solar battery cell 6 was placed between the pair of rails 91 and 91. Next, one end of the light diffusing member 3 was bonded to the surface of the interconnector 1, and the other end was fitted into the groove 83 and held. In this state, by sliding the carriage 80 while pulling the gripping portion 84 of the carriage 80, the light diffusing member 3 fitted in the groove 83 is slid down to the upper part of the interconnector 1, and thereby the light diffusing member 3 is moved to the interface 83. Affixed on the connector 1. By this operation, the light diffusing member 3 was bonded to the interconnector 1.

About the presence or absence of deviation generated in the light diffusing member bonded to the interconnector, the case where the interconnector is visible from the upper part of the solar battery cell is rejected, the case where the interconnector is covered by the light diffusing member and is not visible is accepted, Each was evaluated according to the following criteria.
A: The light diffusing member was attached to the interconnector cell 10 times and never failed.
A: The light diffusing member was attached to the interconnector cell 10 times, and the failure was 2 times or less.
X: The light diffusing member was attached to the interconnector cell 10 times, and there were 3 or more failures.

<Evaluation of microcrack generation>
A solar cell module for evaluation was manufactured as follows. For the polycrystalline 6 inch silicon semiconductor cell (manufactured by Kyocera Corporation) with the interconnector soldered to the solar battery cell, the light diffusing member obtained in the above examples and comparative examples is attached to the upper part of the interconnector soldered to the cell. Then, a light diffusion layer was formed by heat sealing or coating. Using this light diffusion layer, solar cell tempered glass (thickness 3.2 mm) / sealing material EVA (thickness 0.500 mm) / solar battery cell (thickness 0.2 mm) / sealing material EVA (thickness) 0.500 mm) / back surface protection sheet in this order, and a solar cell module was manufactured with a vacuum laminator (“LM-140X200S” manufactured by NPC). The size of the tempered glass was 180 mm square.

  A thermal cycle test (TC test) was used as a verification of the presence or absence of the occurrence of microcracks in the cell due to rapid temperature changes. For the thermal cycle test, “ARS-0680-J” manufactured by Espec was used. The test conditions were changed from 25 ° C. to −40 ° C. over 41 minutes and held at −40 ° C. for 30 minutes. Next, the temperature was changed from −40 ° C. to 85 ° C. over 75 minutes and held at 85 ° C. for 30 minutes. Subsequently, it changed from 85 degreeC to 25 degreeC over 30 minutes. A thermal cycle test was conducted by repeating 200 times under these test conditions.

The presence or absence of microcracks after the thermal cycle test was confirmed and evaluated as follows.
○: Microcracks were not observed.
X: Microcracks were observed.

  An EL device was used for confirmation of microcracks, and the presence or absence of microcracks was determined by comparing images of solar cells before and after the thermal cycle test (TC test). For the EL device, “PVX-300” manufactured by Ites was used.

  In Table 1, the thickness of the light diffusing member of each Example and Comparative Example, the tensile elastic modulus (MPa), and the evaluation of stickability to an interconnector when using the light diffusing member of each Example and Comparative Example, and The evaluation result of the micro crack generation | occurrence | production presence or absence to the photovoltaic cell is shown.

  In the light diffusing member for an interconnector of each example, the total thickness is 20 μm or more and 80 μm or less, and the tensile elastic modulus is 150 MPa or more and 25000 MPa or less, so that the adhesive property to the interconnector is good. In addition, the generation of microcracks was suppressed. On the other hand, in the light diffusing member for interconnectors of Comparative Examples 1 to 4, it was not possible to achieve both the suppression of the occurrence of microcracks and the improvement of the pastability at the same time. Moreover, in the light diffusing member for interconnectors of Comparative Example 5, the total thickness was less than 20 μm, and breakage or the like occurred, so that the operation of attaching to the interconnector itself was impossible. Moreover, in the light diffusing member for interconnectors of Comparative Example 6, since the tensile elastic modulus was too large, adhesion to the interconnector was impossible.

A solar cell module 1 interconnector 3 light diffusing member for interconnector 3a light diffusion layer 3b adhesive layer 4 incident light 5 light 6 solar cell 7 tempered glass 8 sealing material 9 back surface protection sheet

Claims (5)

A light diffusing member for an interconnector disposed on a surface opposite to the solar battery cell of an interconnector that connects adjacent solar battery cells,
A light diffusion layer including at least a resin and inorganic particles;
A light diffusing member for an interconnector having a total thickness of 20 µm or more and 80 µm or less and a tensile elastic modulus of 150 MPa or more and 25000 MPa or less.   The resin is at least selected from the group consisting of ionomers, ethylene-vinyl acetate copolymers, ethylene- (meth) acrylic acid vinyl copolymers, adhesive polyolefin resins, acrylic resins, urethane resins, silicone resins, and unsaturated polyester resins. The light-diffusion member for interconnectors of Claim 1 containing 1 type.   The light diffusion member for an interconnector according to claim 1, wherein the light diffusion layer further includes a phosphor.   The interconnector for solar cells provided with the light-diffusion member for interconnectors of any one of Claims 1-3.   A solar cell module provided with the solar cell interconnector according to claim 4.